The present invention relates to methods for producing chewing gum. More particularly, the invention relates to methods for producing chewing gum containing protein sweeteners which have been treated to produce a delayed release when the gum is chewed.
Thaumatin is an example of a protein sweetener. The sweetness of thaumatin is about 2,000 to 3,000 times sweeter than sucrose on a weight basis, thus making it one of the sweetest known substances. Thaumatin is obtained from the fruit of the tropical plant Thaumatococcus daniellii Benth. of the family Marantaceae. This plant is found in various parts of tropical Africa and has a tetrahedral fruit approximate 4 cm in diameter. Thaumatin can be extracted by the procedures described by van der Well and Loeve, in Eur. J. Biochem. 31 pp. 221-5, (1972) as modified by the teachings of British Pat. No. 1,501,409 and British patent appln. No. 2,015,533A Thaumatin is commercially available from the TATE AND LYLE INDUSTRIES, LTD. of Reading, Berkshire, England
Monellin is another example of a protein sweetener with about half the sweetness potential of thaumatin. Monellin is obtained from the fruit of the tropical plant Dioscoreo-phyllum cumminsii Diels., of the family Menispermaceae. The plant and berries have become known as "Guinea Potato" or "Serendipity Berry." The plant can be found in forests of tropical West Africa and bears grape-like clusters of red berries about 10 mm in diameter. Monellin can be extracted by the procedure described by J.A. Morris et al J. Biol. Chem. 248 (2), 543-9 (1973); or by van der Wel, F.E.B.S. Letters 21(1), 88-90 (1973); or in British Pat. No. 1,337,086.
It has previously been proposed to use thaumatin and monellin to enhance and/or extend the sweetness and/or flavor of chewing gum formulations. One problem which has hindered their use in chewing gum is that the full sweetness and flavor potential of these sweeteners is not realized when they are incorporated in chewing gum. It is currently believed that this phenomenon is caused by a tendency for the sweeteners to become bound up in the gum base, and thus not fully released from the gum during chewing. Added to this is the fact that these sweeteners are extremely costly.
This problem was addressed in U.S. Pat. No. 4,562,076 assigned to the assignee of the present application. According to this patent, the thaumatin and/or monellin is incorporated in a rolling compound for the gum. U.S. Pat. No, 4,642,235 also assigned to the same assignee, describes a method wherein thaumatin or monellin is incorporated into the liquid of a liquid center-filled chewing gum product.
Another problem which has hindered the use of thaumatin or monellin in chewing gum is the fact that since each has such a high sweetness potential, the release of the sweetener during chewing must be delayed in order to avoid an overpowering sweetness and flavor burst upon initial chewing, and to provide for longer lasting sweetness.
In recent years, efforts have been devoted to delaying the release of sweeteners and flavors in various chewing gum formulations. Similarly, efforts have been directed at protecting high-potency sweeteners within the chewing gum formulation, to thereby increase the shelf-stability of the ingredient, i.e. the protection against degradation of the high-potency sweetener over time.
For example, U.S. Pat. No. 4,597,970 to Sharma et al., teaches a process for producing an agglomerated sweetener wherein the sweetener is dispersed in a hydrophobic matrix consisting essentially of lecithin, a glyceride, and a fatty acid or wax having a melting point between 25 and 100.degree. C. The method disclosed uses a spray congealing step to form the sweetener-containing matrix into droplets followed by a fluid bed second coating on the agglomerated particles.
U.S. Pat. Nos. 4,515,769 and 4,386,106, both to Merrit et al., teach a two step process for preparing a delayed release flavorant for a product such as chewing gum. In this process, the water insoluble flavorant, such as an essential oil, is prepared in an emulsion with a hydrophyllic matrix, such as gelatin or gum arabic The emulsion is dried and ground and the particles are then coated with a water impermeable substance, such as shellac or zein.
U.S. Pat. No. 4,230,687, to Sair et al., teaches a process for encasing an active ingredient to achieve gradual release of the ingredient in a product such as chewing gum. The method described involves adding the ingredient to an encapsulating material in the form of a viscous paste. High shear mixing is used to achieve a homogeneous dispersion of the ingredient within the matrix which is subsequently dried and ground.
U.S. Pat. No. 4,139,639, to Bahoshy et al., teaches a process of "fixing" aspartame by co-drying (by spray drying or fluid bed coating) a solution containing aspartame and an encapsulating agent, such as gum arabic, to thereby surround and protect the aspartame during storage in the gum.
U.S. Pat. No. 4,384,004, to Cea et al., teaches a method of encapsulating aspartame with various solutions of encapsulating agents using various encapsulation techniques such as spray drying in order to increase the shelf-stability of the aspartame.
U.S. Pat. No. 4,634,593 to Stroz et al., teaches a method for producing controlled release sweeteners for confections, such as chewing gum. The method taught therein involves the use of an insoluble fat material which is mix mulled with the sweetener.
Naturally, the processes which use spray drying or fluid bed techniques for encapsulating the ingredients involve a relatively large investment in equipment and require skilled operating personnel and sophisticated process controls.
U.S. Pat. 4,292,336 to Latymer et al. describes a process for increasing the heat stability of thaumatin. In this process, the thaumatin is mixed with gelatin at a weight ration of gelatin to sweetener of less than 100:1.
Another problem which has hindered the use of the thaumatin in chewing gum involves the fact that it can have undesirable flavor off-notes. In particular, at certain levels thaumatin is known to have a licorice off-note.
Yet another factor which has hindered the use of thaumatin in chewing gum is the fact that thaumatin is a powder with a low density and has been known to produce an allergic reaction when breathed by certain individuals. Thus, health problems can be created for the workers involved in the chewing gum production if thaumatin is added to the chewing gum formulation neat.